diff --git a/io_win32.cpp b/io_win32.cpp
index fdd86f2d..97cf563e 100644
--- a/io_win32.cpp
+++ b/io_win32.cpp
@@ -155,6 +155,13 @@ mapped_file::size (void) const
 }
 
 
+bool
+mapped_file::empty (void) const
+{
+    return size () == 0;
+}
+
+
 uint8_t*
 mapped_file::begin (void)
 {
diff --git a/io_win32.hpp b/io_win32.hpp
index 8435cfca..08fc63d8 100644
--- a/io_win32.hpp
+++ b/io_win32.hpp
@@ -46,7 +46,9 @@ namespace util {
 
             const uint8_t* data (void) const;
             uint8_t*       data (void);
-            size_t         size (void) const;
+
+            size_t size  (void) const;
+            bool   empty (void) const;
 
             uint8_t*       begin (void);
             uint8_t*       end   (void);